VENICE, Italy—Ingrid (Julianne Moore) is a writer, signing copies of her new book. She’s written it to help process her fears about death, but that hasn’t worked. An old friend, Martha (Tilda Swinton), surprises her at a book signing with some unfortunate news: She is dying from an aggressive cancer. The pair haven’t seen each other in years, but when Ingrid visits Martha in her hospital room, the two immediately reconnect; they haven’t lost a step. Going to the...